As hematopoietic cell transplantation (HCT) has improved in frequency, safety and efficacy over the last two decades, the number of long-term survivors has markedly increased. Children undergoing this intense therapeutic modality are at high risk of a number of late toxicities. HCT-related late effects are a significant cause of morbidity and more importantly, mortality. HCT survivors who are <18yrs of age at the time of transplant face a risk of late mortality that is 17 fold higher than the general population. The majority of these non-relapse related late deaths can be attributed to infectious, cardiac and pulmonary causes. Risk factors for these and other causes of morbidity and mortality in HCT survivors must be identified so that 1) appropriate modifications in therapy can be made and 2) screening and/or intervention trials and health maintenance recommendations for HCT survivors can be developed. Due to the rarity of many of these adverse events, there is a need to follow large cohorts in order to arrive at meaningful associations. Multi-institutional studies allow one to achieve high numbers and also allow generalizability of findings, because they take into account the variability in the transplant practices at the various sites. In the last few years, significant improvements in the ability to perform multi-institutional pediatric HCT studies have combined with the development of a skilled group of pediatric experts in HCT late effects research. With expertise and infrastructure now available to allow this field to move into high-quality multi-center studies, we seek funding for a conference in Arlington, VA in April of 2011 aimed at defining the best questions, approaching them with the most innovative and informative methodologies, and coming to a consensus about how to prioritize the work and move forward. The conference organizing committee is composed of international experts in the fields of late effects and multicenter pediatric HCT research. Conference organizers have assembled a distinguished group of experts who have agreed to address the following areas: 1) methodological challenges in the study of late effects after HCT, 2) studies of biomarkers and/or genetic predisposition to late effects after HCT, and 3) approaches to the study of organ system dysfunction and health-related quality of life after HCT. Specific topics that will be addressed in item number three above include long-term post-HCT immunodeficiency, pulmonary, gastrointestinal, hepatic, renal, cardiovascular, neurocognitive and endocrine dysfunction, and quality of life and functional outcomes after HCT. The goal of the meeting will be to define priorities, establish working groups to move high-priority projects forward, set timelines to achieve established goals, and publish conference conclusions. This meeting will lay the foundation for a new generation of high-quality multi-center late effects studies that will eventually aid in defining approaches aimed at improving long-term outcomes in children undergoing HCT. PUBLIC HEALTH RELEVANCE: Because bone marrow transplantation occurs rarely in children, large studies that could allow us to better understand the seriousness and frequency of adverse medical complications that can occur several years after the transplant have not occurred. This proposal requests funding to support a conference attended by recognized experts in late complications after pediatric transplant therapy aimed at prioritizing topics, choosing the best approaches, and organizing specific efforts to plan studies. These studies will allow us to define aspects of the transplant procedure associated with increased risk, resulting in appropriate modifications of future transplant approaches and allowing the design of screening or intervention trials and health maintenance recommendations for transplant survivors.